Mozilla Firefox ''Host:'' Buffer Overflow

Mozilla Firefox "Host:" Buffer Overflow

Release Date:
September 8, 2005

Date Reported:
September 4, 2005

Severity:
Critical

Vendor:
Mozilla

Versions Affected:
Firefox Win32 1.0.6 and prior
Firefox Linux 1.0.6 and prior
Firefox 1.5 Beta 1 (Deer Park Alpha 2)

Overview:
A buffer overflow vulnerability exists within Firefox version 1.0.6 and all other prior
versions which allows for an attacker to remotely execute arbitrary code on a affected
host.

Technical Details:
The problem seems to be when a hostname which has all dashes causes the NormalizeIDN
call in nsStandardURL::BuildNormalizedSpec to return true, but is sets encHost to an
empty string. Meaning, Firefox appends 0 to approxLen and then appends the long
string of dashes to the buffer instead. The following HTML code below will reproduce
this issue:

'<A HREF=https:--------------------------------------------- >'

Simple, huh? ;-]

Vendor Status:
Mozilla was notified, and im guessing they are working on a patch. Who knows though?

Source: Security Protocols

Thanks for the breaking news!